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/*
*
* Copyright 2015, Google Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
*/
/* I don't like using #ifndef, but I don't see a better way to do this */
#ifndef GRPC_UV
#include <nan.h>
#include <node.h>
#include "call.h"
#include "completion_queue.h"
#include "grpc/grpc.h"
#include "grpc/support/log.h"
#include "grpc/support/time.h"
namespace grpc {
namespace node {
namespace {
/* A worker that asynchronously calls completion_queue_next, and queues onto the
node event loop a call to the function stored in the event's tag. */
class CompletionQueueAsyncWorker : public Nan::AsyncWorker {
public:
CompletionQueueAsyncWorker();
~CompletionQueueAsyncWorker();
/* Calls completion_queue_next with the provided deadline, and stores the
event if there was one or sets an error message if there was not */
void Execute();
/* Returns the completion queue attached to this class */
static grpc_completion_queue *GetQueue();
/* Convenience function to create a worker with the given arguments and queue
it to run asynchronously */
static void Next();
/* Initialize the CompletionQueueAsyncWorker class */
static void Init(v8::Local<v8::Object> exports);
protected:
/* Called when Execute has succeeded (completed without setting an error
message). Calls the saved callback with the event that came from
completion_queue_next */
void HandleOKCallback();
void HandleErrorCallback();
private:
static void TryAddWorker();
grpc_event result;
static grpc_completion_queue *queue;
// Number of grpc_completion_queue_next calls in the thread pool
static int current_threads;
// Number of grpc_completion_queue_next calls waiting to enter the thread pool
static int waiting_next_calls;
};
const int max_queue_threads = 2;
using v8::Function;
using v8::Local;
using v8::Object;
using v8::Value;
grpc_completion_queue *CompletionQueueAsyncWorker::queue;
// Invariants: current_threads <= max_queue_threads
// (current_threads == max_queue_threads) || (waiting_next_calls == 0)
int CompletionQueueAsyncWorker::current_threads;
int CompletionQueueAsyncWorker::waiting_next_calls;
CompletionQueueAsyncWorker::CompletionQueueAsyncWorker()
: Nan::AsyncWorker(NULL) {}
CompletionQueueAsyncWorker::~CompletionQueueAsyncWorker() {}
void CompletionQueueAsyncWorker::Execute() {
result = grpc_completion_queue_next(queue, gpr_inf_future(GPR_CLOCK_REALTIME),
NULL);
if (!result.success) {
SetErrorMessage("The async function encountered an error");
}
}
grpc_completion_queue *CompletionQueueAsyncWorker::GetQueue() { return queue; }
void CompletionQueueAsyncWorker::TryAddWorker() {
if (current_threads < max_queue_threads && waiting_next_calls > 0) {
current_threads += 1;
waiting_next_calls -= 1;
CompletionQueueAsyncWorker *worker = new CompletionQueueAsyncWorker();
Nan::AsyncQueueWorker(worker);
}
GPR_ASSERT(current_threads <= max_queue_threads);
GPR_ASSERT((current_threads == max_queue_threads) ||
(waiting_next_calls == 0));
}
void CompletionQueueAsyncWorker::Next() {
waiting_next_calls += 1;
TryAddWorker();
}
void CompletionQueueAsyncWorker::Init(Local<Object> exports) {
Nan::HandleScope scope;
current_threads = 0;
waiting_next_calls = 0;
queue = grpc_completion_queue_create_for_next(NULL);
}
void CompletionQueueAsyncWorker::HandleOKCallback() {
Nan::HandleScope scope;
current_threads -= 1;
TryAddWorker();
CompleteTag(result.tag, NULL);
DestroyTag(result.tag);
}
void CompletionQueueAsyncWorker::HandleErrorCallback() {
Nan::HandleScope scope;
current_threads -= 1;
TryAddWorker();
CompleteTag(result.tag, ErrorMessage());
DestroyTag(result.tag);
}
} // namespace
grpc_completion_queue *GetCompletionQueue() {
return CompletionQueueAsyncWorker::GetQueue();
}
void CompletionQueueNext() { CompletionQueueAsyncWorker::Next(); }
void CompletionQueueInit(Local<Object> exports) {
CompletionQueueAsyncWorker::Init(exports);
}
} // namespace node
} // namespace grpc
#endif /* GRPC_UV */
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